DE2633746A1 - CIRCUIT ARRANGEMENT FOR THE POWER SUPPLY - Google Patents

Description

PATENT ADVOCATES A. GRÜNECKER

D (PL-ING.

H. KINKELDEY

DR-ING.

W. STOCKMAIR

0 C \ ^ i * 5 7 / C \ DR-INQ.'AeE (CAtTBCW

L W JiJ / HO _K SCHUMANN

OR. RER NAT. - OWL-PHVS

P. H. JAKOB

DlPL-INa

G. BEZOLD

DR RERNAC ' WL-CHBA

8 MUNICH 22

MAXlMlLtANSTRASS * 43

P 10702 27. JuH 1976

NIPPON KOGAKU K. K.

2-3 Marunouchi 3-chome,

Chiyoda-ku

Tokyo / JAPAN

Circuit arrangement for power supply

The invention relates to a circuit arrangement for power supply and in particular a supply circuit with constant voltage regulation.

Most of the electronic devices, circuits and components required up to now a temperature compensation to ensure that the circuits used in it are independent to maintain their normal functioning due to temperature changes or fluctuations in temperature.

Such temperature compensations have until now been made by exploitation the fact that the voltage drop occurring across diodes in the forward direction or the base-emitter voltage of transistors have a temperature-dependent curve or a temperature-dependent characteristic value However, temperature-dependent characteristic curves, courses or characteristic values only show a fixed, predetermined value and therefore can

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TELEPHONE (Oaa) 22 38 83 TELEX 05-39380 TEAMME MONAPAT TELEKOPIEREFl

a temperature compensation - if at all - not with the required Accuracy can be carried out.

There is therefore a need for a supply source with constant voltage regulation in which the temperature-dependent Gradients, characteristic values and characteristics can be changed in a desired manner, with the circuit arrangement provided for this be of simple construction and still allow a high level of accuracy in temperature compensation.

The invention is therefore based on the object of providing a circuit arrangement of this type which satisfies the requirements mentioned to accomplish.

This object is achieved according to the invention by the circuit arrangements specified in claims 1 and 12.

Advantageous embodiments of the circuit arrangements according to the invention are identified in the sub-proverbs.

The invention thus creates a supply circuit with constant voltage regulation, in which the temperature-dependent courses, characteristic values and characteristic curves are selected in the manner required in each case with the possibility of avoiding a temperature dependency at all.

The inventive circuit has a simple structure and yet operates with high accuracy and reliability Z ^u.

In the circuit arrangement according to the invention for the voltage supply With temperature-dependent characteristic curves and characteristic values, these characteristic curves and characteristic values can be easily entered as required Setting and changing the resistance values can be selected.

The invention is explained below with reference to the drawings, for example explained in more detail. Show it:

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Pig. 1 the constant voltage circuit with variable, temperature-dependent Characteristic curves and parameters according to a first embodiment of the invention,

Fig. 2 the constant voltage circuit with variable, temperature-dependent Characteristic curves and parameters according to a second embodiment according to the invention,

Fig. 3 shows the constant voltage circuit with variable, temperature-dependent Characteristic curves and parameters according to a third embodiment according to the invention in connection with a test circuit for the supply voltage,

Fig. 4 · the constant voltage circuit with variable, temperature-dependent Characteristic curves and parameters according to a fourth embodiment according to the invention in connection with a temperature compensation circuit and

5 shows the graph of the temperature dependency as a function of the value of the voltage division ratio y in the fourth embodiment.

In the exemplary embodiment of the invention shown in FIG. 1, a constant current source 1, a resistor Ry, and a diode D ^ are connected in series across a battery E. The connection point between the constant current source 1 and the resistor Eyj is connected to the inverting input of an operational amplifier A via a resistor Ro and the connection point between the resistor R ^ and the diode B ^ is connected to the non-inverting input of the operational amplifier A. Between the output C of the operational amplifier A and the negative pole of the battery E, namely the ground connection or the common connection G, there is a diode D- ,, a resistor R? and a resistor R ^ in series. Between the connection point a of the resistors R 1 and R ^ and the inverting input of the operational amplifier A is a feedback diode Dp. The connection point between the resistor R, and the diode D, is = ■ provided with the reference symbol b. The mode of operation of the circuit practically does not change even if a resistor is used instead of the constant current source Λ. this

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is also the case when the connection point between the resistors R ₁ and E _{2 is} connected to the positive terminal of the battery E.

The operational amplifier A, the resistors E ₁ , E ₂ , the diodes D ₁ , D ₂ and the constant current source 1 together form a first circuit part. At the connection point a between the resistors E 1 and E ^, which is the output of the first circuit part, a voltage V _{2 occurs} with a positive temperature-dependent curve.

The diode D i forms a second circuit part. The voltage across the diode D, has a negative temperature-dependent As will be described later, and therefore the voltage at the connection point b has with respect to the voltage at the output C of the operational amplifier A a negative, temperature-dependent Course.

The resistors E ₁ and E 2 together form a third circuit part.

The operation of the present embodiment is described below.

Assume that the gain of the operational amplifier A sufficiently large and the voltages at the inverting input and at the non-inverting input of the operational amplifier A are the same. In this case it is

I ₁ E ₁ = I ₂ E ₂ (1)

Here, I _{1 is} the current flowing through resistor E ₁ and diode D _{1 and I 2 is} the current flowing through resistor E ₂ and diode Dp. The voltage V ₁ at the non-inverting input of the operational amplifier A is also equal to the voltage drop occurring _{through the constant current I 1} across the diode D _1. In general, the current-voltage relationship of a

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logarithmic forming and conversion component, for example a diode or the like, express the following equation:

ir k. T ä ¹ D ( _O \

V_ = —-—- JCn —γ - \ .Z)

D q Ig

V ^ is the voltage drop across the diode in the forward direction, k is the BoItzmann constant, T is the absolute temperature, q is the electron charge, I _{D is} the current flowing through the diode and Ig is the saturation current flowing in the reverse direction in the diode. V ^ is expressed by the following equation:

(3)

The voltage Vp at junction a is of course equal to the voltage V _x . minus the voltage drop that occurs across diode 1 * 2 due to the current Ip. Vp is therefore given by:

The equation for Vp results from equations (1) and (4)

The voltage V ^ occurring at the connection point a, that is to say at the output of the first circuit part, depends only on the resistors IL and Rp ab; it is not only independent of the Supply voltage, but also has a positive, temperature-dependent, proportional to the absolute temperature Course.

In addition, the current I _{2 is} relative to that through the resistor E ₇ . flowing stream very small. Hence the one through the

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Current Ip at the resistor R ₄ , the voltage drop occurring is negligible. The voltage V, at the connection point b is given by the following equation:

* + R ₄
T ^ ^V 2

+ R ₄ . I ^

In (-J.) (6)

K I

Substituting equation (1) into equation (6) results in the voltage V ^:

^E 3 ^{+ E} 4 λ ^H 2

(7)

From the preceding description it follows that the voltage V, at the connection point b is only determined by the resistors R ^, R ₂ ' ^ß 3 UBd ^R 4 and is not only independent of the supply voltage, but also a positive temperature-dependent, the absolute one Temperature proportional characteristics.

As is known, the voltage occurring across a diode in the forward direction has a negative temperature-dependent curve in the order of magnitude of -2.2 (mV / ° C). The voltage V at the output C is therefore the sum of the voltage V ^ at the junction point b, which has a positive temperature dependency, and ^{4 of} the voltage occurring across the diode D ₇₅ , which has a negative temperature dependency.

For example, in the embodiment shown in FIG. 1, the case should be considered in which, at a reference temperature of 20 ° C., the voltage V _Q at the output C is on a predetermined

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given value is maintained, which remains unaffected by temperature changes or fluctuations.

As from equation (7) for the voltage V, at connection point b what can be seen is the factor

_k S ₃ ⁺ % ..CnC - ^ - O

the constant of proportionality for the absolute temperature T.

Therefore, by choosing the sizes of the various resistances, the constant of proportionality can be made equal to 2.2 (mV), so that the voltage V _Q at output C can be kept at a predetermined value which is equal to (273 + 20) χ 2.2 = 645 (mV) plus the voltage drop occurring at 20 ° C across diode D _7. By suitable definition of the relationship or the ratio between the various components, the voltage V at the output C can furthermore be influenced in such a way that a desired constant voltage occurs there without any temperature dependency. '

By suitably selected values for the resistors R ^, R ₂ , R * and R ^, the voltage V _Q at the output C can also be chosen so that it has either a positive or a negative temperature dependency.

The same effect can also be produced by placing one or more diodes in parallel with diode Dg or become.

In the present embodiment, the resistors R ₇ , and R ,. used. However, the resistor R ₂ is not necessarily required, as can be seen from equation (7). In other words, the resistor R ^ can be short-circuited or replaced by a normal line. When using the resistors R ₇ . and R ^ however, it is easier

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the proportionality constants of the absolute temperature T can be set.

Fig. 2 is a second Ausführungsbei game of the present Invention, in which the diodes that are connected to the two inputs of the operational amplifier A, compared to Fig. 1 are reversed. The circuit elements that have the same function as the circuit elements in the first embodiment s example are given the same reference numbers provided, and the voltage values that have the same index numbers, are the same. Details of the operation of this second embodiment are the same as those of the first embodiment and therefore do not need to be explained again.

In Fig. 3 is a third embodiment of the present Invention in connection with an economy test circuit shown.

The resistors R,. And R ^ are between the output C of the operational amplifier & and the common or terminal G in series. The output voltage V _{2 of} the first circuit part 'occurs at the connection point a between the resistors R * and R ^. A constant current source 1a and a transistor Tr ^ are connected in series across the connection terminals of the battery E and the output C of the operational amplifier A is connected to the base of the transistor Tr ^.

The transistor Tr ^ is instead of the diode D, of the first embodiment used. The voltage Vp at junction a, which is the output voltage of the first circuit part is given by equation (5) and proportional to the absolute temperature T, as described in detail in connection with the first embodiment. thats why the voltage V, given at the output C of the operational amplifier A. by

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^R 3 ⁺ \ . ο "2 I" * T

as was also the case in equation (7). The voltage V, is therefore proportional to the absolute temperature T. Since the base-emitter voltage V _{BE of} the transistor Tr _{1 has} a negative temperature dependency, the emitter voltage V _{Q of} the transistor Tr _{1 is} the sum of the voltage V ^ with a positive temperature dependency and the voltage Vgg with a negative temperature dependence * Therefore, it can - be chosen so the emitter voltage V of the transistor Tr ₁ that no temperature dependency occurs, and by suitable choice of values for which - as previously described in connection with the first embodiment Resistors E ₁ , E ₂ , E ₅ and E ^.

The voltage divider resistors Ec and E ^ are between the Terminals of battery E in series. The voltage Vd appearing at the connection point d between these resistors increases therefore also decreases with decreasing supply voltage.

One input of a comparator stage 2 is connected to the emitter of the transistor Tr ₁ and the other input of the comparator stage 2 is connected to the connection point d between the voltage divider resistors Ec and E _c . A light-emitting diode 3 is located between the output of the comparator stage 2 and the common or ground connection G

The input voltages V _Q and Vd of the comparison stage 2 are therefore the same when the supply or battery voltage has a certain value. When the supply or battery voltage is above this value, V _{Q is} less than Vd and when the supply or battery voltage is below this value, V _{Q is} greater than Vd. The comparator stage 2 therefore switches the light-emitting diode 3 on or off depending on the magnitude of the voltage Vd in relation to the voltage V _Q,

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so that the status of the supply or battery voltage is displayed will.

In order to give the output voltage a desired temperature dependency, the resistance values for the resistors E ^, E ₂ , E, and E ^ are changed in the first, second and third exemplary embodiments described so far, or several modes are placed in parallel with the diode D ₂ , so that the output voltage of the first circuit part, which has a positive temperature dependency, is changed.

According to the invention, however, it is also possible to change the output voltage of the second circuit part, which has a negative temperature-dependent profile, in order _{to generate a voltage V 0} which can have any desired temperature dependency. This is to be described below using a fourth exemplary embodiment.

lig. 4- shows the fourth embodiment of the present Invention in connection with the temperature compensation circuit for a light emitting diode.

In the fourth embodiment, which has a variable temperature-dependent characteristic, a voltage divider resistor E, - is parallel to the diode D ^ of the circuit shown in Fig. 1 and the output voltage Y _Q is tapped from the voltage divider point f of this resistor.

With such a circuit arrangement, the temperature dependency of the voltage V _Q at the voltage divider point, f, is changed as a function of the voltage division ratio § * of the voltage divider resistor Ec.

In Fig. 5 the relationship between the voltage division ratio? the voltage dividing resistance Ec, and the temperature dependency of the voltage Y _{Q will be} explained.

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If the voltage division ratio f of the voltage divider Ec is zero (cf. parameter <? _O in lig. 5), the voltage V at the voltage divider point f is equal to the voltage V at the connection point b and has a positive temperature dependency. When the voltage dividing ratio. ξ is gradually increased, the voltage across the diode D, which has a negative temperature dependency, is added to the voltage YT , which has a positive temperature dependency. At a certain voltage division ratio £ ^ the positive and negative temperature-dependent characteristics equalize each other so that the voltage V _Q at the voltage divider point f has no temperature dependency (cf. parameter f y. In FIG. 5).

If the voltage division ratio is increased further, the voltage V can have a negative temperature (see parameter g ~ in Pig. 5) ·

the voltage V is given a negative temperature dependence

As shown in FIG. 4, a component 4, which requires temperature compensation, can be connected between the collector of the transistor Tr ₂ and the positive terminal of the battery E. The emitter of the transistor Tr g is connected to the minus terminal of the battery E (that is, the common or ground connection G) via a resistor Rg. The voltage V _Q , which occurs at the voltage divider f of the voltage divider resistor Rc, is applied to the base of the transistor T ^.

It is assumed, for example, that the temperature-compensated component Λ is a light-emitting diode. The intensity of the light emitted by the light-emitting diode decreases with increasing temperature. If the current I flowing through the light-emitting diode is increased with increasing temperature, the intensity of the light emitted by the diode remains constant in this case, regardless of whether changes in temperature occur. This can be done by reducing the voltage division ratio § of the voltage divider resistor R ₁ - and the voltage

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divider resistance Rc is set so that the voltage V ₀ at the voltage divider point f has a positive temperature dependence. The collector current I of the transistor T ^ is therefore increased when the temperature rises, so that the light-emitting diode 4 emits light with constant intensity regardless of a temperature rise.

Venn the circuit arrangement according to the invention as a circuit is used where the output voltage is positive Has temperature dependency, the circuit arrangement according to the invention can be very advantageous as a precise temperature compensation circuit can be used for a light emitting diode in which the intensity of the emitted light decreases with increasing temperature. The present invention can be used particularly advantageously as a compensation circuit in connection with cameras or the like.

It should also be noted that in the circuit shown in FIG also several diodes connected in series can be used instead of the diode D, if one is required to create a wide range of negative temperature characteristics.

The present invention thus provides a supply circuit which Constantly regulates the supply voltage with high accuracy, and which has a simple structure, the temperature dependency being changed in a desired manner and also being set in this way can be that no temperature dependency occurs. This change in temperature dependence is in the inventive Circuit arrangement carried out by a simple operation, namely by changing resistance values.

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Claims (1)

- 13 claims 1. J circuit arrangement for the voltage supply, characterized by a first circuit part (A, R ₁ , E ₂ , D ₁ , D ₂ , 1) for providing a temperature-dependent output voltage with an operational amplifier (A) having a first and a second input and an output, a first resistor (R ₂ ) 'one terminal of which is connected to the first input of the operational amplifier (A), a second resistor (R ₁ ), one terminal of which is connected to the second input of the operational amplifier (A) and the other terminal of which is connected to the other terminal of the first resistor (R ₁ ) is connected and a first and second logarithmic converter el em ent (D ₁ , D ₂ ), which generate a temperature-dependent voltage proportional to the logarithm of the current flowing through it, the first being logarithmic Converter element (D ₁ ) between the second input of the operational amplifier (A) and a ground connection (G) of the circuit arrangement r voltage supply and the second logarithmic converter element (D ₂ ) between the first input and the output of the operational amplifier (A) is through a second circuit part (D ^), which provides a temperature-dependent output voltage, the temperature dependence of the temperature of the temperature dependence of the first circuit part (A, R ₁ , R ₂ , D ₁ , D ₂ , 1) provided voltage is opposite and by a third circuit part (R ^, R ^), which is connected to both the first and the second circuit part (A, R ₁ , R ₂ , D ₁ , D ₂ , 1; D,) is connected and the output voltages of the first and second circuit parts (A, R ₁ , R ₂ , D ₁ , D ₂ , 1; D,) combined. Circuit arrangement according to Claim 1, characterized in that the output voltages of the first and second circuit parts (A, R ₁ , Rp, D ₁ , D ₂ , 1; D ^) are proportional to the temperature. 609 8 8 6/0885 3 · Circuit arrangement according to claims 1 and 2, characterized in that the third circuit part (R ^, R ^) the mutual compensation of the temperature-dependent characteristics of the first and the second circuit part (A, R ^, R ^ ,, D ^, Dp , 1; D _7. ) And provides a voltage that has no temperature dependence. 4-. Circuit arrangement according to one of Claims 1 to 3, characterized in that the third circuit part (R ^, R ^) comprises resistors in order to increase the proportionality constant of the temperature dependence for the first and / or second circuit part (A, R ^., Rp, D ^ , Dp, 1; D _7. ). 5 · Circuit arrangement according to one of Claims 1 to 4-, characterized characterized in that the first and second logarithmic translation elements (D-, Dp) have a first and a second, respectively Diode is. 6. Circuit arrangement according to one of claims 1 to 5 »characterized in that the second circuit part (D, _{) comprises a third diode (D 7.} ), Whose first connection to the output (C) of the operational amplifier (A) and its second connection is connected to one terminal of the second diode (D2), the other terminal of the second diode (Dp) being connected to the first input of the operational amplifier (A). 7- circuit arrangement according to any one of claims 1 to 6, characterized in that the resistors _{comprise a voltage part ending resistor (R 7.} , R ^), one connection with the second connection of the third diode (Di), the other connection with the Ground connection (G) of the circuit arrangement for the voltage supply and its connection (a), at which the divided voltage occurs, to which one connection of the second diode (D ₂ ) is connected. 609 88 6/0885 8. Circuit arrangement according to one of claims 1 to 6, characterized in that the resistors have a voltage divider resistor (Ec), which is connected to the third diode (D,) and its connection (f) to which the divided voltage occurs, the output of the circuit arrangement for the voltage supply is (Fig. 4 ·). 9 · Circuit arrangement according to one of Claims 1 to 8, characterized in that the second circuit part contains a transistor (Tr ₁ ) and the third circuit part (E ,, E ^) with the output (C) of the operational amplifier (A) and the base of the transistor (Tr ^) is connected (Fig. 3) 10. Circuit arrangement according to one of claims 1 to 9> thereby characterized in that the output voltage, which is obtained by combining the output voltages of the first and second Circuit part (A, E ^, Ep, D ^, Dp, 1; D ^) in the third Circuit part (E ^, E ^) results in a positive temperature dependence having. 11.. Circuit arrangement according to one of Claims 1 to 10, ~ characterized by a transistor (Tr ₂ ), at the base of which the combined output voltage is applied, and a _{light-emitting diode (4 ·) connected to the collector of the transistor (Tr 2} ), wherein the collector current of the transistor (Tr _? ) can have a positive temperature dependence so that the intensity of the light emitted by the light-emitting diode (4 ·), which can have a negative temperature dependency, can be kept constant regardless of temperature changes. 12. Circuit arrangement for voltage supply, characterized by a circuit part (A, Ey ₁ , B ₂ , D ^, D ₂ * 1), which provides a first voltage with a positive temperature dependence, a circuit ^ part (D ^), which has a second Voltage with a negative temperature dependency ready- 609886/0885 and a circuit part (R ₅₅ , R ^) which combines the first and the second voltage and generates an output signal as a function of the first and the second voltage, the circuit part (A, R ₁ , R2 ' ^D i' ^D 2 '^ ^1, which provides the first voltage, comprises an operational amplifier stage for generating a voltage proportional to the absolute temperature. 13 · Circuit arrangement according to Claim 12, characterized in that the circuit part (D,) which supplies the second voltage provides a diode connected to the output (C) of the operational amplifier (A) of the operational amplifier stage includes. 14. Circuit arrangement according to one of claims 12 and 15j characterized in that the operational amplifier stage two between the inputs of an operational amplifier (A) series resistors (R ^, Rp) includes and provides a voltage that is proportional to the logarithm of the size ratio of the resistances (Rx., Rp) times the absolute temperature. 15- Circuit arrangement according to one of claims 12 to 14, characterized in that the operational amplifier stage comprises two logarithmic converter elements (D ^, IX,) each connected to the inputs of the operational amplifier (A), one (Dp) of these logarithmic converter elements (D ^, D ₂ ) connects one of the inputs to the output (C) of the amplifier (A). 609886/0885 Blank page